JP5747326B2 - Propylene production method - Google Patents

Description

  The present invention relates to a method for producing propylene, in which acetone and hydrogen are produced from ethanol and water, and the produced acetone and hydrogen are reacted to produce propylene.

  Since ethanol can be produced from raw materials other than petroleum by fermentation of biomass or the like, in recent years, it has attracted attention as a raw material for producing chemical products that does not rely on fossil raw materials. A method of reacting ethanol using a catalyst to convert it into an oxygen-containing compound having 3 or more carbon atoms, particularly acetone, has been known for a long time.

  Acetone can be converted to propylene by hydrogenation and dehydration, but until now, only the method of conversion using hydrogen generated in the processing step of fossil raw materials has been implemented, and fossil raw materials are used as hydrogen sources. No unnecessary method has been established. In addition, the process for producing acetone (cumene method phenol production apparatus and the like) and the hydrogen production apparatus (methane reformer and the like) are separate production processes, which are inefficient.

  Here, methods for reacting ethanol using a catalyst and converting it to acetone are disclosed in Non-Patent Documents 1 to 6, Patent Document 1 and the like. These describe that hydrogen, acetaldehyde, ethylene, carbon dioxide and the like are produced as by-products.

Moreover, although the reduction | restoration method (hydrogenation method) of acetone is disclosed by patent documents 2-5 etc., all use pure hydrogen, According to patent document 2, especially, the used hydrogen has the higher purity. Is preferred.
On the other hand, Patent Document 6 describes that it is not necessary to use hydrogen having a particularly high purity, and hydrogen containing impurities such as methane, ethane, and nitrogen can be used, but it is produced as a by-product in the reaction of ethanol. There is no suggestion as to whether or not hydrogen containing impurities such as aldehyde, carbon monoxide and carbon dioxide can be used. In particular, carbon monoxide is known to be a poison for the hydrogenation catalyst, and the use of by-product gas containing these impurities has not been studied.

  Furthermore, when reducing acetone by such a method, the main product is isopropanol, and in order to make propylene the main product, a complicated process combined with a solid acid catalyst such as zeolite is further added. It was necessary (Patent Documents 7 and 8).

JP 2009-209059 A Japanese Patent Laid-Open No. 3-141235 JP-A-3-41038 Japanese Patent Laid-Open No. 2-270829 JP-A-3-133941 JP 2002-128716 A WO2010 / 064500A1 WO2010 / 106966A1

Journal of the Indian Chemical Society, Industrial and News Edition, Vol. 16, pp. 109-113 (1953) Journal of the Chemical Society, Chemical Communications, 1987, pp. 394-395 (1987) Applied Catalysis, 52, 237-248 (1989) Journal of Materials Chemistry, Vol. 4, pp. 853-858 (1994) Applied Catalysis A: General, 172, 117-129 (1998) The Chemical Society of Japan, 1997, No. 1,33-36 pages (1997)

As described above, a method for continuously and efficiently producing propylene from ethanol has not been established.
Therefore, an object of this invention is to provide the manufacturing method of propylene which can manufacture propylene from ethanol continuously and efficiently.

  As a result of diligent research to solve the above problems, the present inventors have conceived the present invention described below and found that the problems can be solved. That is, the present invention is as follows.

[1] Propylene production method for producing propylene by producing acetone and hydrogen from ethanol and water and reacting the produced acetone and hydrogen, wherein iron, zinc, alkali metal and / or alkali The acetone and hydrogen are produced in the presence of an iron-zinc-alkali-containing catalyst containing an earth metal and having a molar ratio of alkali metal and / or alkaline earth metal to zinc of 0.2-2. Indium-containing catalyst composed of any one of indium oxide and indium-containing composite oxide, or indium containing 1% by mass or more of the indium as an element with respect to the total mass of the catalyst. A method for producing propylene, comprising producing the propylene in the presence of a catalyst.
[2] The method for producing propylene according to [1], wherein the indium-containing catalyst further contains one or more metals selected from Group 4 and Groups 8 to 13 (excluding indium) as elements in the periodic table.
[3] Propylene according to [1] or [2], in which surplus hydrogen when propylene is produced by reacting acetone and hydrogen is used again to produce propylene from the acetone and hydrogen. Manufacturing method.
[4] The method for producing propylene according to any one of [1] to [3], wherein hydrogen is further supplied from outside the system when acetone and hydrogen are reacted to produce propylene.
[5] The method according to any one of [1] to [4], wherein a part of the hydrogen after producing acetone and hydrogen from ethanol and water is used for reduction of a by-product produced during the production. Propylene production method.

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of propylene which can manufacture propylene from ethanol continuously and efficiently can be provided.
This makes it possible to produce useful chemicals by effectively using biomass, and to contribute to the suppression of fossil resource consumption and the suppression of the release of carbon dioxide originating from fossil raw materials into the atmosphere.

In the present invention, acetone and hydrogen are produced from ethanol and water (hereinafter, sometimes referred to as “acetone and hydrogen production process” for convenience), and the produced acetone and hydrogen are reacted to produce propylene. This is a method for producing propylene (hereinafter sometimes referred to as “propylene production process” for the sake of convenience). The production process of acetone and hydrogen and the subsequent production process of propylene are performed continuously.
Hereinafter, each step will be described in detail.

[1. Acetone and hydrogen production process]
Examples of the catalyst used in the process of producing acetone and hydrogen from ethanol include catalysts containing iron, zinc and the like as disclosed in Non-Patent Documents 1 to 6 and Patent Document 1, but in the present invention, iron Use a zinc-alkali containing catalyst.
The iron-zinc-alkali-containing catalyst contains iron, zinc, an alkali metal and / or an alkaline earth metal, and a molar ratio of the alkali metal and / or alkaline earth metal to zinc (hereinafter, “ M / Zn "(M: sometimes referred to as alkali metal and / or alkaline earth metal) is 0.2-2.

  According to the conventional knowledge in this reaction (Non-Patent Document 2 and Non-Patent Document 3), the activity decreases when an alkali metal is introduced, and the activity is increased when the molar ratio of alkaline earth metal to zinc is increased from 0.1.・ It is known that selectivity decreases rapidly.

  From these findings, it can be said that the M / Zn range of the iron-zinc-alkali-containing catalyst is unique. That is, in the catalyst, when M / Zn is less than 0.2 and when the molar ratio is greater than 2, the activity and selectivity are lowered, and the efficiency is deteriorated. The molar ratio is preferably 0.2-1.

  Further, the molar ratio of zinc to iron in the catalyst is preferably 0.01 to 10, more preferably 0.02 to 5, and further preferably 0.05 to 1. By the said molar ratio being 0.01-10, a side reaction can be suppressed and acetone selectivity can be improved. In addition, the introduction of zinc reduces the amount of acid, thereby suppressing the dehydration reaction and increasing the selectivity of acetone production.

The iron-zinc-alkali-containing catalyst can be prepared by any method as long as the composition is within the above-described component ratio range.
For example, a method in which a base such as aqueous ammonia is dropped into an aqueous solution in which a salt of iron, zinc, alkali metal and / or alkaline earth metal prepared to the above component ratio is dissolved, and a method of firing after filtration, The powder may be prepared by impregnating a commercially available iron oxide powder with an aqueous solution of zinc salt, alkali metal salt and / or alkaline earth metal salt, followed by firing.

  The catalyst powder thus prepared becomes a molded catalyst that can be used in a fixed bed reactor by kneading and molding with a general binder (silica, alumina, silicate, etc.).

  As ethanol used for the reaction in the production process of acetone and hydrogen, general ethanol produced by various methods such as fermentation can be used, and it may contain impurities such as water and acetaldehyde. When the ratio of ethanol and water contains water, acetone selectivity is improved. Therefore, the molar ratio of water to ethanol is preferably 0.1 to 10, and preferably 0.5 to 5. More preferably, it is more preferably 1 to 3. When ethanol having a purity higher than these ratios is used, it is preferable to separately supply water to the reactor so that the above ratio is obtained.

The reaction in this step can be carried out in any form such as a fixed bed, moving bed, fluidized bed, etc., but is a fixed bed type reaction in which ethanol and water are supplied to a tubular reactor filled with a powdered or molded catalyst. It is preferable to implement.
The space velocity in the reaction is preferably set to 400～6500H ^-1, and more preferably a 400~4000h ^-1.
The reaction temperature is preferably 250 to 600 ° C, more preferably 300 to 550 ° C, and further preferably 350 to 500 ° C.
The reaction pressure can be any of reduced pressure, normal pressure, and increased pressure, but is usually performed in an atmosphere of normal pressure to slightly increased pressure.
This reaction can also be carried out in the presence of nitrogen, hydrogen, other hydrocarbon gases, and the like.

[2. Propylene production process]
The catalyst used in the process of reacting acetone and hydrogen produced through the production process of acetone and hydrogen (production process of propylene) has a hydrogenation ability of acetone and a dehydration ability of hydride, and has high resistance to impurities. A catalyst must be used, and a catalyst containing indium (indium-containing catalyst) is particularly suitable. The indium-containing catalyst has the catalytic action of both the hydrogenation reaction of acetone and the dehydration reaction of acetone hydride. By using this catalyst, this reaction step becomes substantially one step, It can be a simple and efficient manufacturing process.

  As the indium-containing catalyst, a catalyst made of any of indium oxide and a composite oxide containing indium (hereinafter sometimes referred to as “first indium-containing catalyst”), or indium supported on a carrier, A catalyst containing 1% by mass or more of the indium as an element with respect to the total mass of the catalyst (hereinafter, sometimes referred to as “second indium-containing catalyst”) is used.

Here, as a preferable example of the first indium-containing catalysts include indium oxide (In ₂ O _3). Examples of the type of indium oxide include cubic or amorphous. The indium content (as oxide) in the first indium-containing catalyst is preferably 1 to 100% by mass, and more preferably 20 to 100. The catalyst activity and propylene selectivity can be made high by being 1 to 100% by mass.

  The first indium-containing catalyst includes a method in which a salt containing a metal component (nitrate, sulfate, chloride, etc.) is baked as it is in air, or a base such as ammonia water is dropped into an aqueous solution containing the metal component. It can be obtained by a method of forming a precipitate and baking after filtration.

Further, the content of indium as an element in the second indium-containing catalyst is 1% by mass or more, and preferably 2% by mass or more. When it is less than 1% by mass, the catalytic activity and propylene selectivity are lowered.
Examples of the carrier include alumina, silica, silica alumina, zirconia, zinc oxide, titania, magnesia and the like. The second indium-containing catalyst can be prepared by a normal impregnation method.

  In order to adjust the activity and selectivity of the catalyst, it is preferable that a metal other than indium further contains one or more metals selected from Group 4 and Groups 8 to 13 (excluding indium) as elements in the periodic table. . In this case, these metals are preferably contained as metal oxides.

  The indium-containing catalyst according to the present invention can be used as a desired particle size (for example, a particle size of 300 to 600 μm by sieving), or can be used by drying it as a slurry, or clay minerals, etc. It can be used in a shape mixed and molded with a binder.

  In the production process of propylene according to the present invention, the effluent (including acetone and hydrogen) from the production process of acetone and hydrogen can be used as it is as a reaction raw material without any particular purification. The production process of propylene can be carried out in any form such as a fixed bed, moving bed, fluidized bed, etc., like the production process of acetone and hydrogen, but in general, it is filled with a powdered or molded indium-containing catalyst. A fixed bed reactor is used.

  The reaction temperature is 250 to 600 ° C, preferably 300 to 550 ° C, more preferably 350 to 550 ° C. The reaction pressure can be any of reduced pressure, normal pressure, and increased pressure, but is usually performed in an atmosphere of normal pressure to slightly increased pressure. This reaction can also be carried out in the presence of nitrogen, hydrogen, other hydrocarbon gases, and the like. Since the outlet effluent of the propylene production process contains surplus hydrogen, the outlet hydrogen can be recycled to the inlet of the acetone and hydrogen production process or the propylene production process.

  The reaction mode in the reaction performed in the presence of the indium-containing catalyst is not particularly limited, but is preferably carried out in a fixed bed flow type. When the reaction is performed in a fixed bed flow type, the reaction is performed by fixing the indium-containing catalyst according to the present invention in the reaction tube and supplying acetone and hydrogen into the reaction tube.

The space velocity in the reaction is preferably set to 500～5000H ^-1, and more preferably a 500~1000h ^-1.

Acetone can be supplied into the reaction tube together with water (water vapor). The ratio of water to acetone is preferably 0.1 to 10, more preferably 1 to 5. By supplying water (steam), carbon adhesion on the catalyst and reduction of the catalyst can be suppressed.
Note that a carrier gas such as nitrogen or helium may be supplied to the reaction tube.

  As described above, propylene can be continuously and efficiently produced from ethanol. In addition, an indium containing catalyst and an iron-zinc-alkali containing catalyst form a separate catalyst layer, and use for reaction.

  Below, the manufacturing method of propylene of this invention is demonstrated, showing a reaction formula about each process.

The main reaction in the production process of acetone and hydrogen is represented by the formula (1).
2C ₂ H ₅ OH + H ₂ O → CH ₃ COCH ₃ + 4H ₂ + CO ₂ Formula (1)

The main reaction in the production process of propylene is represented by the formula (2).
CH ₃ COCH ₃ + H ₂ → CH ₂ ═CH—CH ₃ + H ₂ O (2)

Accordingly, the total main reaction of these steps is represented by the formula (3).
2C ₂ H ₅ OH → CH ₂ ═CH—CH ₃ + 3H ₂ + CO ₂ Formula (3)

Hydrogen and carbon dioxide (CO ₂ ) are produced as main by-products at the outlet of the continuous reaction from the production process of acetone and hydrogen to the production process of propylene. This carbon dioxide is derived from biomass (carbon neutral) when bioethanol is used as a raw material, and does not increase the amount of carbon dioxide in the atmosphere.
However, from the viewpoint of effective utilization of resources, by using the surplus hydrogen produced as a by-product here and reducing CO ₂ , which is also a by-product, in the reaction represented by the formula (4), It can be converted to methanol (methanol conversion step).
In addition, as a catalyst of a methanol conversion process, the catalyst etc. which are described in Unexamined-Japanese-Patent No. 6-179632 are mentioned.
3H ₂ + CO ₂ → CH ₃ OH + H ₂ O Formula (4)

From the above, the entire reaction up to the acetone and hydrogen production process, the propylene production process and the methanol conversion process is represented by the formula (5).
2C ₂ H ₅ OH → CH ₂ ═CH—CH ₃ + CH ₃ OH + H ₂ O (5)

Example 1
(Preparation of iron-zinc-alkali-containing catalyst)
Commercially available zinc nitrate hexahydrate (Wako Pure Chemical Industries, Zn (NO ₃ ) ₂ .6H ₂ O, purity 99.0% or more) 3.74 g, Strontium nitrate (Wako Pure Chemical Industries, Sr (NO _{3 2} ) Purity: 98.0% or more) 1.09 g was dissolved in 4.00 g of ion-exchanged water to prepare an aqueous solution containing zinc and strontium.

  An aqueous solution containing zinc and strontium was added to 10.03 g of commercially available iron oxide hydroxide (manufactured by Kanto Chemical Co., FeO (OH), purity of 95.0% or more) dried at 120 ° C. for 18 hours or more in a constant temperature dryer. In this state, the mixture was kneaded for 5 minutes to produce a slurry substance.

The slurry material prepared in air 200 cm ³ / min in a muffle furnace for 3 hours baking at 120 ° C. 6 hours (at 5 ° C. / min temperature increase) drying, further 600 ° C. (heating at 5 ° C. / min) And a reddish brown solid (SrO / ZnO / Fe ₂ O ₃ catalyst) containing iron, zinc and strontium was obtained.

  Elemental composition analysis of the obtained catalyst was performed by ICP (inductively coupled plasma) emission spectroscopy. The composition analysis by ICP emission spectroscopic analysis was performed with an ICPE-9000 type ICP emission spectroscopic analyzer manufactured by Shimadzu. As a measurement sample, an acid solution was prepared by dissolving the catalyst to be analyzed with a mixed acid of hydrofluoric acid and hydrochloric acid.

  From the measurement results, the molar ratio of zinc to iron in the catalyst was 0.12, and the molar ratio of strontium to zinc was 0.39. The obtained catalyst was pulverized before use and classified into 300 to 600 μm.

(Preparation of indium-containing catalyst)
A slurry obtained by adding 4.53 g of ion-exchanged water to 10.00 g of commercially available indium oxide (Kanto Chemical Co., In ₂ O ₃ , purity of 99.9% or more) dried at 120 ° C. for 18 hours or more in a constant temperature dryer. And kneaded for 5 minutes.

The obtained slurry-like substance was air 200 cm ³ / min. In a muffle furnace. The mixture was calcined at 800 ° C. (heated at 1 ° C./min.) For 5 hours to obtain a yellow solid (In ₂ O ₃ catalyst). The obtained catalyst was pulverized before use and classified into 300 to 600 μm.

(Propylene production method)
Ethanol conversion reaction using an iron-zinc-alkali-containing catalyst and an indium-containing catalyst was performed as follows.
The formulas for the conversion of ethanol and the propylene yield (each amount based on mole) were calculated by applying the following formulas.
Ethanol conversion rate = 100 × (reactor inlet ethanol amount−reactor outlet ethanol amount) / reactor inlet ethanol amount Equation (6)

Propylene yield = 100 × (reactor outlet propylene amount × 3) / (reactor inlet ethanol amount × 2) (7)

  The reaction tube used for the reaction has a double structure, the outside is a SUS316 tube (φ27.2 × t5.5 mm), the inside is a quartz electric melting tube (φ15 × t2.0 mm), A quartz thermocouple inner tube (φ3.5 × t1.0 mm) is provided inside.

The upper stage of the reaction tube was filled with 1.21 g and 3.70 g of SrO / ZnO / Fe ₂ O ₃ catalyst and the lower stage with In ₂ O ₃ catalyst, respectively. Each catalyst layer was held with quartz wool filled in the upper and lower sides.

The temperature of the catalyst layer is 400 ° C. (upper) and 525 ° C. (lower) by external heating while flowing nitrogen at 29.0 cm ³ / min (25 ° C., converted to 1 atm, the same applies hereinafter) into the reaction tube filled with the catalyst. The temperature was raised to 1 hour and maintained for 1 hour.

Thereafter, the reaction was carried out by continuously supplying ethanol, water, and nitrogen from the inlet side of the reaction tube at normal pressure so as to have a molar ratio of 19:29:52 (total gas flow rate on the inlet side: 29.0 cm). ³ / min).

  One hour after the start of the reaction, the reaction tube outlet gas was analyzed by an on-line gas chromatograph. As a result, it was confirmed that the ethanol conversion was 100% and propylene was produced in a yield of 21%.

(Example 2)
Assuming hydrogen recycling, the ethanol conversion reaction was carried out under the same conditions as in Example 1 except that the feedstock at the inlet of the reaction tube was ethanol, water, hydrogen, and nitrogen (molar ratio: 19: 29: 42: 10). (Inlet side total gas flow rate: 29.0 cm ³ / min).

  One hour after the start of the reaction, the reaction tube outlet gas was analyzed with an on-line gas chromatograph. As a result, it was confirmed that the ethanol conversion was 100% and propylene was produced in a yield of 46%. Further, the reaction was continued as it was for 20 hours, and the outlet gas was similarly analyzed. As a result, the ethanol conversion was 100%, and the propylene yield was 46%.

Claims (5)

Propylene production method for producing propylene by producing acetone and hydrogen from ethanol and water, and reacting the produced acetone and hydrogen,
An iron-zinc-alkali-containing catalyst containing iron, zinc, alkali metal and / or alkaline earth metal, and having a molar ratio of alkali metal and / or alkaline earth metal to zinc of 0.2 to 2 Producing the acetone and hydrogen in the presence of
An indium-containing catalyst comprising either indium oxide or a composite oxide containing indium, or an indium-containing catalyst comprising indium supported on a support, the indium being contained in an amount of 1% by mass or more as an element with respect to the total mass of the catalyst Propylene is produced in the presence of   The method for producing propylene according to claim 1, wherein the indium-containing catalyst further contains one or more metals selected from Group 4 and Group 8 to 13 (excluding indium) as elements in the periodic table.   The production of propylene according to claim 1 or 2, wherein surplus hydrogen produced by reacting acetone and hydrogen to produce propylene is used again to produce propylene by reacting acetone and hydrogen. Method.   The method for producing propylene according to any one of claims 1 to 3, wherein hydrogen is supplied from outside the system when acetone and hydrogen are reacted to produce propylene. The propylene according to any one of claims 1 to 4 , wherein a part of the hydrogen after producing acetone and hydrogen from ethanol and water is used for reduction of by-products produced during the production. Production method.